Cartridge actuated ordnance filter

ABSTRACT

The present invention comprises a capacitor, of sufficient area to cover the glass seal of a cartridge actuated ordnance device, comprising a low pass filter. This capacitor connects to the leads of the cartridge actuated ordnance device in a fashion that covers the glass seal of the cartridge. Although the capacitor is not directly contacting the glass seal, it is located proximately so that very few frequencies of EMR can enter the seal, wherein a safe level of EMR is achieved. The capacitor also filters both EMR and ESD that come through the leads of the cartridge.

STATEMENT OF GOVERNMENT INTEREST

[0001] The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention pertains to an improvement to cartridgeactuated ordnance. More particularly, the present invention adds orimproves the following safety feature to such devices: shielding fromelectromagnetic radiation (EMR); filtering to eliminate EMR conductedalong the firing leads of the device; and, increased protection againsthuman borne electrostatic discharge (ESD) when handling the devices. Thepresent invention accomplishes these tasks by incorporating a low-passfilter into the design of current devices.

SUMMARY OF THE INVENTION

[0004] The present invention comprises a capacitor, of sufficient areato cover the glass seal of a cartridge actuated ordnance device, havinga capacitance value of from about 0.4 microfarads to about 1.1microfarads. This capacitor connects to the leads of the cartridgeactuated ordnance device in a fashion that covers the glass seal of thecartridge. Although the capacitor is not directly contacting the glassseal, it is located proximately so that very few frequencies of EMR canenter the seal, wherein a safe level of EMR is achieved. The capacitoralso filters both EMR and ESD that comes through the leads of thecartridge.

[0005] This present invention is specifically designed to protectcartridge actuated ordnance from high power EMR resulting from twobodies that are in proximity, or, are intermittently making contact.This environment is commonly known as Hazards of ElectromagneticRadiation to Ordnance (HERO). HERO tests are conducted at a broad rangeof frequencies using continuous wave and pulsed power modulations. Theinteraction between the two bodies, such as between a cartridge actuatedordnance device and a person's body loading such a device, causes arcingat various frequencies. The present invention also provides protectionagainst ESD through ionization and filtering.

[0006] The present invention was developed in order to providesufficient EMR protection to meet Military Standard 464 for HERO. Priorto this invention, cartridge actuated ordnance often failed to meet thisstandard. Although a single capacitor is used in order to accomplishthis and other objectives, the configuration and placement of thecapacitor would not lead one skilled in the art to deduce thatsufficient HERO protection would result.

[0007] Accordingly, it is the object of this invention to provide adevice that shields a cartridge actuated ordnance from EMR.

[0008] It is a further object of this invention to provide a device thatfilters EMR and ESD from a cartridge actuated ordnance.

[0009] This invention accomplishes these objectives and other needsrelated to protecting cartridge actuated ordnance devices from EMR andESD.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate embodiments of theinvention, and, together with the description, serve to explain theprinciples of the invention.

[0011]FIG. 1 is a cross-sectional view of a cartridge incorporating anembodiment of the present invention.

[0012]FIG. 2 is a top view of the present invention of the embodimentshown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] The invention, as embodied herein, comprises a filtering devicethat provides electromagnetic radiation and electrostatic dischargeprotection for cartridge actuated ordnance. The cartridge portion of acartridge actuated ordnance normally comprises a glass seal thatprovides a vacuum within the cartridge in order to function properly inactuating ordnance. In most configurations, the cartridge also comprisestwo leads that extend past the glass seal in order to attach thecartridge to the ordnance for actuation. The present invention comprisesa capacitor that has an area sufficient to substantially cover the glassseal. The capacitor also comprises a low pass filter. The capacitor isconnected to the cartridge leads so that it substantially covers theglass seal as noted above, but does not actually contact the seal. Thisconfiguration provides protection from electromagnetic radiation (EMR)and electrostatic discharge (ESD) through two different methods. First,by covering the glass seal, EMR is physically blocked from entering thecartridge by capacitor. Second, the capacitor filters high frequency EMRand ESD attempting to enter the device through the leads.

[0014] Referring to FIG. 1, the cartridge 100 comprises two leads 102that extend from the sides of a glass seal 104. The glass seal 104 is astandard feature on most cartridges 100 used for actuating ordnance. Theglass seal is placed on the cartridge in order to form a vacuum for theinitiator portion of the cartridge 100. The present invention comprisesa capacitor 106 that has an area sufficient to substantially cover theglass seal 104. This enables the capacitor 106 material itself tosubstantially block EMR from entering the cartridge 100 through theglass seal 104. In one embodiment of the invention, the capacitor 106comprises a discoidal capacitor. In another embodiment of the invention,the capacitor 106 comprises a faraday cage to substantially cover theglass seal 104. The capacitor 106 also comprises a low pass filter. Morepreferably, the capacitor comprises a capacitance of about 0.4microfarads to about 1.1 microfarads, and comprises a most preferredcapacitance of approximately 0.5 microfarads. The capacitor 106comprises a low pass filter in order to filter out EMR and ESD passingthrough the leads 102. The capacitor 106 is able to perform both ofthese functions due to its proximity to the entry point of the EMR andESD, the leads 102.

[0015] The capacitor 106 is connected to the cartridge 100 by the twoleads 102 so that it substantially covers the glass seal 104 as notedabove, but does not actually contact the glass seal 104. In theembodiment of the invention shown in FIG. 2, the capacitor 106 comprisesholes 210 formed within the capacitor wherein leads 102 fit through theholes. Most standard cartridges 100 comprise two leads 102, so,therefore, the preferred capacitor 106 comprises two holes 210.

[0016] The present invention also comprises a method of blockingelectromagnetic radiation and filtering electromagnetic radiation andelectrostatic discharge from cartridge actuated ordnance. This methodcomprises providing the filtering device disclosed above.

[0017] What is described are specific examples of many possiblevariations on the same invention and are not intended in a limitingsense. The claimed invention can be practiced using other variations notspecifically described above.

What is claimed is:
 1. A filtering device that provides electromagneticradiation and electrostatic discharge protection for cartridge actuatedordnance wherein the cartridge has a glass seal and a plurality ofleads, comprising: a capacitor, having an area sufficient to cover theglass seal, comprising a low pass filter, connected to the leads andsubstantially covering the glass seal wherein the capacitorsubstantially blocks electromagnetic radiation from entering the glassseal and provides filtering for both electromagnetic radiation andelectrostatic discharge.
 2. The filtering device of claim 1, wherein thecapacitor comprises a discoidal capacitor.
 3. The filtering device ofclaim 2, wherein the capacitor further comprises a faraday cage tosubstantially cover the glass seal.
 4. The filtering device of claim 3,wherein the capacitor comprises a capacitance from about 0.4 microfaradsto about 1.1 microfarads.
 5. The filtering device of claim 4, whereinthe capacitor comprises a capacitance of about 0.5 microfarads.
 6. Thefiltering device of claim 5, further comprising a plurality of holesformed within the capacitor wherein the plurality of leads fit throughthe holes.
 7. The filtering device of claim 6, comprising two holesformed within the capacitor.
 8. A method of blocking electromagneticradiation and filtering electromagnetic radiation and electrostaticdischarge from cartridge actuated ordnance wherein the cartridge has aglass seal and a plurality of leads, comprising the step of: providing afiltering device comprising a capacitor, being discoidal and having anarea sufficient to cover the glass seal, comprising a capacitance ofapproximately 0.5 microfarads, connected to the leads and substantiallycovering the glass seal wherein the capacitor substantially blockselectromagnetic radiation from entering the glass seal and providesfiltering for both electromagnetic radiation and electrostaticdischarge.